App links intent filters in assetlinks.json not working on Android

Question

My app defines the intent filters to handle URL's from my site defined by

<intent-filter android:autoVerify="true">
  <action android:name="android.intent.action.VIEW"/>
  <category android:name="android.intent.category.DEFAULT"/>
  <category android:name="android.intent.category.BROWSABLE"/>
  <data android:host="www.host.com" android:scheme="http"/>
</intent-filter>
<intent-filter android:autoVerify="true">
  <action android:name="android.intent.action.VIEW"/>
  <category android:name="android.intent.category.DEFAULT"/>
  <category android:name="android.intent.category.BROWSABLE"/>
  <data android:host="www.host.com" android:scheme="https"/>
</intent-filter>

The app correctly detects URL's of the correct host but queries the user whether to open them in the app or browser. I tried using the App links verification as specified here: https://developer.android.com/training/app-links/index.html

As seen in my server logs, when installing the app, the device queries /well-known/assetlinks.json and it responds with a 200 status. Testing the digital assets file using the

https://digitalassetlinks.googleapis.com/v1/statements:list?source.web.site=https://<domain1>:<port>&relation=delegate_permission/common.handle_all_urls

API and it found no errors.

The SHA256 in the assetlinks.json file was obtained using

keytool -list -v -keystore my-release-key.keystore 

the same .keystore of which the app was signed.

Running adb shell dumpsys package d returns that the link verification status is "ask" meaning that verification failed. Why might verification be failing?

Answer 1

For us it was Windows line endings!

Testing with "https://digitalassetlinks.googleapis.com/v1/statements:list?source.web.site=https://domain1:port&relation=delegate_permission/common.handle_all_urls" proved invaluable as it gave us an "Could not parse statement list (not valid JSON)" error which led us to the problem.

TIP: It was good to use the 'Save File' button in the Android Studio App Links Assistant instead of copying and pasting as we did - that way it generates the file itself and is guaranteed not to have this issue.